AC-Side Symmetrically-Split Inverter for Power Decoupling
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Solution Overview
Problem
Existing single-phase inverters face inefficiencies due to double-frequency ripples on the DC side during power conversion, leading to increased costs and losses, as well as the short service life of electrolytic capacitors used for decoupling, and incomplete decoupling despite additional switching devices.
Innovation Solution
An AC-side symmetrically-split single-phase inverter design utilizing an H-bridge structure with parallel half-bridge units and filter capacitors on the AC side to compensate double-frequency power without additional switching devices, achieving complete decoupling by controlling the common-mode voltage of symmetrically-split filter capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If large electrolytic capacitors are connected in parallel on the DC side to buffer double-frequency power, then the double-frequency ripples are suppressed, but the service life of the inverter is reduced due to the short life of the capacitors
Solution Approach 1:
The patent extracts the power decoupling function from the DC side electrolytic capacitors and relocates it to the AC side filter capacitors. By taking out the harmful dependency on short-lived electrolytic capacitors and transferring the decoupling task to the AC side, the invention eliminates the service life limitation while maintaining ripple suppression capability.
Solution Approach 2:
The patent introduces the AC side filter capacitors as an intermediary element to perform the power decoupling function. Instead of using DC side capacitors directly, the invention employs the AC side filter capacitors as a mediator to buffer double-frequency power, thereby achieving decoupling without compromising inverter longevity.
2Object-affected harmful factors
If additional switching devices are added to construct power decoupling circuits, then decoupling capability is improved, but system costs and losses increase
Solution Approach 1:
The patent makes the AC side filter capacitors multi-functional by assigning them both their original filtering role and the additional power decoupling function. This universal utilization of existing components eliminates the need for separate decoupling circuits with additional switching devices, thereby reducing system loss while maintaining effective decoupling capability.
Solution Approach 2:
The patent merges the power decoupling function with the existing AC side filter capacitors. By combining multiple functions (filtering and power decoupling) into a single component set, the invention avoids the energy losses associated with additional switching devices and decoupling circuits, achieving cost-effective and efficient ripple suppression.
3Object-affected harmful factors
If additional switching devices are added to construct power decoupling circuits, then decoupling capability is improved, but device complexity increases
Solution Approach 1:
The patent employs the AC side filter capacitors to perform multiple functions simultaneously - traditional AC filtering and power decoupling. This multi-functionality eliminates the need for separate decoupling circuits and additional switching devices, thereby maintaining simple circuit structure while achieving effective decoupling of double-frequency ripples.
Solution Approach 2:
The patent combines the power decoupling function with the existing AC side filter capacitor structure. By merging decoupling capabilities into the already-present filter components, the invention avoids increasing device complexity, maintaining an elegant and simple overall system architecture without requiring extra switching devices or complex control circuits.
Data Source
AI summary
An alternating current (AC)-side symmetrically-split single-phase inverter for decoupling, which includes an H-bridge inverter, the H-bridge inverter includes an upper half-bridge structure and a lower half-bridge structure that are symmetrical to each other, the upper half-bridge structure includes an upper half-bridge first unit and an upper half-bridge second unit in parallel, the upper half-bridge first unit includes an insulated-gate bipolar transistor G1, a diode D1, and a capacitor C3 in parallel, the upper half-bridge second unit includes an insulated-gate bipolar transistor G3, a diode D3, and a capacitor C4 in parallel; and the lower half-bridge structure includes a lower half-bridge first unit and a lower half-bridge second unit in parallel, the lower half-bridge first unit includes an insulated-gate bipolar transistor G2, a diode D2, and a capacitor C1 in parallel, the lower half-bridge second unit includes an insulated-gate bipolar transistor G4, a diode D4, and a capacitor C2 in parallel.